Eyeing up the Future of the Pupillary Light Reflex in Neurodiagnostics

Diagnostics, Год журнала: 2018, Номер 8(1), С. 19 - 19

Опубликована: Март 13, 2018

The pupillary light reflex (PLR) describes the constriction and subsequent dilation of pupil in response to as a result antagonistic actions iris sphincter dilator muscles. Since these muscles are innervated by parasympathetic sympathetic nervous systems, respectively, different parameters PLR can be used indicators for either or modulation. Thus, provides an important metric autonomic system function that has been exploited wide range clinical applications. Measurement using dynamic pupillometry is now established quantitative, non-invasive tool assessment traumatic head injuries. This review examines more recent application diagnostic conditions, varying from neurodegenerative disease exposure toxic chemicals, well its potential diagnosis infectious disease.

Язык: Английский

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Standards in Pupillography

Frontiers in Neurology, Год журнала: 2019, Номер 10

Опубликована: Фев. 21, 2019

The number of research groups studying the pupil is increasing, as publications. Consequently, new standards in pupillography are needed to formalize methodology including recording conditions, stimulus characteristics, well suitable parameters evaluation. Since description intrinsically photosensitive retinal ganglion cells (ipRGCs) there has been an increased interest and broader application ophthalmology other fields psychology chronobiology. Colour plays important role not only but also clinical observational therapy studies like gene hereditary degenerations psychopathology. Stimuli can vary size, brightness, duration, wavelength. Stimulus paradigms determine whether rhodopsin-driven rod responses, opsin-driven cone or melanopsin-driven ipRGC responses primarily elicited. Background illumination, adaptation state, instruction for participants will furthermore influence results. This standard recommends a minimum set variables be used specified publication methodologies. Initiated at 32nd International Pupil Colloquium 2017 Morges, Switzerland, aim this manuscript outline based on current knowledge experience experts order achieve greater comparability pupillographic studies. Such particularly facilitate proper by researchers field. First we describe general standards, followed specific suggestions concerning demands different targets research: afferent efferent reflex arc, pharmacology, psychology, sleepiness-related animal

Язык: Английский

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Melanopsin contributions to non-visual and visual function

Current Opinion in Behavioral Sciences, Год журнала: 2019, Номер 30, С. 67 - 72

Опубликована: Июль 27, 2019

Melanopsin is a short-wavelength-sensitive photopigment that was discovered only around 20 years ago. It expressed in the cell bodies and processes of subset retinal ganglion cells retina (the intrinsically photosensitive cells; ipRGCs), thereby allowing them to signal light even absence cone rod input. Many fundamental properties melanopsin signalling humans for both visual (e.g. detection, discrimination, brightness estimation) non-visual function melatonin suppression, circadian phase shifting) remain be elucidated. Here, we give an overview what know about contributions function.

Язык: Английский

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Melanopsin photoreception contributes to human visual detection, temporal and colour processing

Scientific Reports, Год журнала: 2018, Номер 8(1)

Опубликована: Фев. 23, 2018

Abstract The visual consequences of melanopsin photoreception in humans are not well understood. Here we studied using a technique photoreceptor silent substitution with five calibrated spectral lights after minimising the effects individual differences optical pre-receptoral filtering and desensitising penumbral cones shadow retinal blood vessels. We demonstrate that putative melanopsin-mediated image-forming vision corresponds to an opponent S-OFF L + M-ON response property, average temporal resolution up approximately 5 Hz, >10x higher thresholds than red-green colour vision. With capacity for signalling integrating slowly changing lights, melanopsin-expressing intrinsically photosensitive ganglion cells maybe fifth type peripheral

Язык: Английский

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Cone and melanopsin contributions to human brightness estimation

Journal of the Optical Society of America A, Год журнала: 2018, Номер 35(4), С. B19 - B19

Опубликована: Янв. 29, 2018

We determined the contributions of cone and melanopsin luminance signaling to human brightness perception. The absolute four narrowband primary lights presented in a full-field Ganzfeld was estimated two conditions, either luminance-equated (186.7−1,867.0 cd·m−2) or (31.6−316.3 cd·m−2). show that estimations for each light follow an approximately linear increase with increasing (in log units), but are not equivalent equated luminance. Instead, result from combined interaction between signaling. Analytical modeling wavelength-dependent coefficients signifies positively correlates magnitudes, has contribution components, one is additive second negative, implying adaptation process. These results provide new framework evaluating physiological basis perception have direct practical applications development energy-efficient sources.

Язык: Английский

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Evening home lighting adversely impacts the circadian system and sleep

Scientific Reports, Год журнала: 2020, Номер 10(1)

Опубликована: Ноя. 5, 2020

The regular rise and fall of the sun resulted in development 24-h rhythms virtually all organisms. In an evolutionary heartbeat, humans have taken control their light environment with electric light. Humans are highly sensitive to light, yet most people now use until bedtime. We evaluated impact modern home lighting environments relation sleep individual-level sensitivity using a new wearable spectrophotometer. found that nearly half homes had bright enough suppress melatonin by 50%, but wide range individual responses (0-87% suppression for average home). Greater evening relative individual's was associated increased wakefulness after Homes energy-efficient lights double melanopic illuminance incandescent lighting. These findings demonstrate significantly affects circadian system, specific is unpredictable.

Язык: Английский

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Publication guidelines and recommendations for pupillary measurement in psychophysiological studies

Psychophysiology, Год журнала: 2022, Номер 59(4)

Опубликована: Март 22, 2022

A variety of psychological and physical phenomena elicit variations in the diameter pupil eye. Changes size are mediated by relative activation sphincter pupillae muscle (decrease diameter) dilator (increase diameter), innervated parasympathetic sympathetic branches, respectively, autonomic nervous system. The current guidelines intended to inform guide psychophysiological research involving measurement (1) summarizing important aspects concerning physiology pupil, (2) providing methodological data-analytic recommendations, (3) briefly reviewing that modulate pupillary reactivity. Because increased ease tractability measurement, goal these is promote accurate recording, analysis, reporting data research.

Язык: Английский

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Light-induced charge generation in polymeric nanoparticles restores vision in advanced-stage retinitis pigmentosa rats

Nature Communications, Год журнала: 2022, Номер 13(1)

Опубликована: Июнь 27, 2022

Abstract Retinal dystrophies such as Retinitis pigmentosa are among the most prevalent causes of inherited legal blindness, for which treatments in demand. prostheses have been developed to stimulate inner retinal network that, initially spared by degeneration, deteriorates late stages disease. We recently reported that conjugated polymer nanoparticles persistently rescue visual activities after a single subretinal injection Royal College Surgeons rat model . Here we demonstrate can reinstate physiological signals at cortical level and visually driven when microinjected 10-months-old rats bearing fully light-insensitive retinas. The extent restoration positively correlates with nanoparticle density hybrid contacts second-order neurons. results establish functional role organic photovoltaic restoring degenerate retinas intense retina rewiring, stage disease patients subjected prosthetic interventions.

Язык: Английский

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Quadrant Field Pupillometry Detects Melanopsin Dysfunction in Glaucoma Suspects and Early Glaucoma

Scientific Reports, Год журнала: 2016, Номер 6(1)

Опубликована: Сен. 13, 2016

Abstract It is difficult to detect visual function deficits in patients at risk for glaucoma (glaucoma suspects) and early disease stages with conventional ophthalmic tests such as perimetry. To this end, we introduce a novel quadrant field measure of the melanopsin retinal ganglion cell mediated pupil light response corresponding typical glaucomatous arcuate defects. The melanopsin-mediated post-illumination (PIPR) was measured 46 different including suspects compared healthy group 21 participants no disease. We demonstrate that superonasal PIPR differentiated from controls fair (AUC = 0.74) excellent 0.94) diagnostic accuracy, respectively. provides linear functional correlate structural nerve fibre thinning patients. This first report stimulation detects dysfunction pre-perimetric may have future implications treatment decisions suspects.

Язык: Английский

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The Method of Silent Substitution for Examining Melanopsin Contributions to Pupil Control

Frontiers in Neurology, Год журнала: 2018, Номер 9

Опубликована: Ноя. 27, 2018

The human pupillary light response is driven by all classes of photoreceptors in the eye-the three cones, rods, and intrinsically photosensitive retinal ganglion cells (ipRGCs) expressing photopigment melanopsin. These photoreceptor have distinct but overlapping spectral tuning, even a monochromatic with wavelength matched to peak sensitivity given will stimulate photoreceptors. method silent substitution uses pairs lights ("metamers") selectively class while keeping activation others constant. In this primer, we describe provide an overview studies that used it examine inputs response.

Язык: Английский

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